A. Chaiken, L.J.
Terminello, and J. Wong
Lawrence Livermore National Laboratory, Livermore, CA
94550
G.L. Doll
GM Research and Development Laboratory, Warren, MI
48090
Soft x-ray core-level photoabsorption has been measured from
three forms of boron nitride, namely the hexagonal (hBN),
cubic (cBN), and incoherent (iBN) phases. The B 1s and N 1s
photoabsorption spectra of the hBN sample show evidence of
both s*- and p* -empty states, indicative of sp2
bonding, while the cBN absorption spectra exhibits only
sp3 bonding in absorption features characteristic
of the zincblende structure. The incoherent phase of BN in
the form of a thin film on a Si substrate possesses s* and p*
states similar to hBN. The B 1s p* absorption features of the
iBN film show an angular dependence which suggests that the
microstructure consists of hexagonal-phase layer planes
oriented normal to the BN/Si interface.